Junctions of ends of continuous belts, also called conveyor belts, transfer conveyors, endless belts, belts, etc, are well-known for various applications, i.e. in mines, public works, the food industry and many other fields. Such end junctions are of two main types: direct junctions by gluing or curing the ends of the conveyor belts prepared for this purpose, and the junctions using devices added at each one of the two ends of the belt either with clamps, rivets, screws or with claws or hooks joined to the junction devices. Such junction devices include series of U-shaped staples including chain links or lugs which are positioned astride on each one of the ends of the belt, which are simply cut transversally with respect to the belt, perpendicularly to the longitudinal direction or travel direction thereof. The chain links of one of the series of staples fastened at one end of the belt are interleaved with the chain links of the other series of staples fastened on the second end of the belt, a connecting and articulation rod being alternately introduced into a chain link of the first series and a chain link of the second series and so on up to the last chain link. It should be understood that such an assembly then operates as a hinge.
The staples each include an upper plate and a lower plate running on from one or several chain links, generally two chain links, such plates being used for fastening the chain links as mentioned above using clamps, rivets or other similar means. They are delivered in divisible belts forming series of juxtaposed staples connected by the metal of the juxtaposed plates, with the metal being provided with a groove, which makes it possible to take the number of staples required at the time of the mounting from a belt including a large number of staples by separating them.
The other kind of staples for the junction of conveyor belts is that of staples with claws. Originally, individual staples were used, which were made of metal wire, bent in a U shape and including bent points analogous to the staples called “hog ring” staples used, for example, when manufacturing bed bases, spring seats and spring mattresses. Such staples were used, for example, to make relatively thin belt junctions or conveyor belt junctions. In order to avoid a conflict between the points fixing such staples overlapping with respect to the end of the conveyor belts, the U-shaped folding was shifted which resulted in branches with different lengths, the claws of which could not conflict when bracing the staples on the ends of the conveyor belts. The staples of this type, which are subsequently called generation I staples, are described for example in several prior documents relating to improvements to the first-generation staples, which are considered as known as from 1935: refer to the German patent 648 538 (Paul Wever) filed on 9 Aug. 1935, the French patent 2 055 625 filed on 24 Jul. 1970, with a conventional priority of the application of the German utility model G 69 29 255.3 filed on 24 Jul. 1967 (Thomas Joseph Heimbach GmbH), the U.S. Pat. No. 5,048,675 dated 6 Feb. 1991, with a priority of the German utility model 90 165 86 (Mühlen Sohn GmbH) dated Jun. 12, 1990.
Such patents illustrate the state of the basic art relating to clawed junction staples, which are subsequently called “generation I” staples. As shown in the figures, these are individual staples having the shape of an open U, made of wire, each including two bent points, which are positioned by braced on the end of a conveyor belt, with the bottom of the U overlapping such end to form, with the other staples of the series, a series of links which can be interleaved with other links positioned on the other end of the conveyor belt. Such documents clearly show that, in order to avoid a conflict between the lower claw and the upper claw of the same staple, either the shape of the claws is modified (last patent mentioned above), or the length of the upper and lower branches of the same staple is modified. The first patent mentioned above alternately uses a short and a long staple and so on. This demonstrate that, for a very long time, as from the generation I staples, industrialists had thought of the necessity to avoid as much as possible tearing the end of the conveyor belt by longitudinally distributing the points of the individual claws, in order to avoid a “dotted” effect.
One improvement consisted in joining such individual staples with a continuous bar connecting the upper claws which were shifted with respect to the lower claws, which were running on from the links, with the upper claws being positioned on either side of the longitudinal axis of the chain links which is the same as that of the lower claws. To make such staples, these were cut in a sheet metal strip or strap. Such staples are also called subsequently generation II staples.
The publication of the patent application EP 0 752 542 A1 (Sülzle) added to generation II staples bars connecting two lower clamps. However such (generation II) staple belts had several drawbacks:                the continuous bar connecting the upper staples made the device rigid widthways of the belt,        the number of claws per link was only two, which did not enable a secure anchoring on the links in the presence of strong punctual or even more extended tractions.        
The present invention aims at providing a junction device for a conveyor belt using series of a new kind of staples provided with flexible properties, while securing the anchoring of the links at the edges of the conveyor belt ends thanks to a geometry which authorizes the use of a much greater number of claws per link, which results in a fastening creating solidarity between the links and the device being thus capable of resisting more important tractions affecting the conveyor belt and thus the junction without any damage for the ends of the conveyor belt. This object is reached using a junction device for conveyor belts composed of a first series of chain links or lugs liable to be fastened on one of the ends of a conveyor belt, and of a second series of chain links or lugs liable to be fastened on the other end of said conveyor belt, with the links of both series being fastened to the respective ends of the conveyor belt so as to protrude with respect to such ends, both series of links being able to be assembled in an articulated way using a connecting and articulation rod successively fitted into a chain link of the first series, then into a chain link of the second series and so on, the chain links of both series being fastened to the respective ends of the conveyor belt having been previously interleaved by bringing together the two ends of the conveyor belt, characterized in that in each one of the two series of chain links, the chain links are connected to fastening plates, the upper branch of a first chain link being connected to an upper plate and the upper branch of a second chain link, adjacent to the first chain link being connected to said upper plate, the lower plate of said second chain link being connected to a lower plate, the lower branch of a third chain link adjacent to the second chain link being connected to said lower plate and so on, forming a meander-like disposition liable to receive, between the upper and lower plates, one end of a conveyor belt with the upper and respectively lower plates being provided with claws or hooks, the points of which are globally oriented downwards as regards the upper plates and globally upwards as regards the lower plates, such claws being positioned on one edge or on edges of the plates and/or inside the surface of the plates.
Another object of the present invention is to facilitate the positioning of the series of the staples according to the invention by integrating a means for blocking the series of staples along the end of the conveyor belt. This aim is reached thanks to stops, the manufacturing of which is easy thanks to the geometry of the invention, with the plates including stops, each being made of a sheet metal piece cut at the same time as the other elements, chain links, plates and claws, this piece of sheet metal being connected to the plate by a folding line and a protruding approximately at right angles with respect to the plane of the plate, in the space located between the upper and the lower plates, where the end of the conveyor belt must be inserted, with the folding line being located at the rear of the chain links, at the place where the front edge of the conveyor belt end must be located.